001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.math4.legacy.analysis;
019
020import java.util.function.DoubleBinaryOperator;
021
022/**
023 * An interface representing a bivariate real function.
024 *
025 * @since 2.1
026 */
027@FunctionalInterface
028public interface BivariateFunction extends DoubleBinaryOperator {
029    /**
030     * Compute the value for the function.
031     *
032     * @param x Abscissa for which the function value should be computed.
033     * @param y Ordinate for which the function value should be computed.
034     * @return the value.
035     */
036    double value(double x, double y);
037
038    /** {@inheritDoc} */
039    @Override
040    default double applyAsDouble(double x, double y) {
041        return value(x, y);
042    }
043}